1. Field of the Invention
This invention relates to devices, systems and methods for mounting solar panels on a pitched roof.
2. Discussion of State of the Art
There is a growing market for alternative energy. Alternative energy includes energy that is generated from wind turbines, water powered turbines, and energy from the sun. Alternative energy not only potentially provides cleaner sources of energy that are good for the environment, but the relative low cost of operating and maintaining an alternative energy system, such as a photovoltaic power system, has given an individual home owner the ability to generate his own power at a cost that is close to the cost of purchasing energy off of the national grid. Thus, solar generated electricity is not only a way of making the environment cleaner; it is a means for greater energy independence at a competitive cost. The cost of generating electricity by photovoltaic systems typically require government incentives and tax credits to make it financially enticing for most investors. Even so, the break even point for a solar panel system is typically about 8 years.
Should photovoltaic cells become less expensive or more efficient, the overall cost would provide incentive to more homeowners, landowners or business owners to invest in the more environmentally-friendly photovoltaic system. A significant part of the cost of a solar panel system is the installation cost and the cost of the racking system. Reducing the cost of racking system can be accomplished by making the parts easier to manufacture and therefore cheaper. Improvements that make the system easier or faster to install can also reduce the cost of installation bringing photovoltaic technology closer to being an affordable alternative to conventional energy sources.
Photovoltaic cells can be mounted on a flat roof system or a pitched roof system. Pitched roof mounting systems are typically designed for the type of roof and building material. Most homes are wood frame houses with composition shingles made of fiberglass and/or asphalt. The roofs are pitched at an angle that is typically between 15 degrees to 60 degrees radian from horizontal. The photovoltaic mounts for this type of roof are typically nailed or screwed into the underlying roof or supporting rafters.
UNIRAC® SOLARMOUNT® Installation with Top Mounting Clamps, Installation Manual 201.1 (2005) and U.S. Des. Pat. No. D496,248 shows a pitched roof mounting system that employs a network of rails supported by posts that are screwed into the underlying rafters. The photovoltaic panels are then fastened to the rails. However, securing a system of rails to a roof with a pitch can be dangerous and requires multiple steps. A jig is required to ensure that the rail support posts are fastened in the right place. Rails are long, relatively heavy and awkward to handle. However, rails allow the clamps to slide into position along the rail allowing greater flexibility in positioning the fasteners along the length of the rail. It would be desirable to support photovoltaic panels on a system that does not require installing long rails on a pitched roof.
SunPower is a manufacturer of solar panels and mounting systems. They produce a solar panel mount for asphalt composition shingle roof houses. See SunPower Dealer Technical Support (December 2007). Sun Power produces a pitched roof mount that comprises a base plate with two extrusions that support the solar panel. In a gap between the extrusions is a center bolt that has a clip that secures the solar panel to the extrusions. Two plates extend horizontally outward from the extrusions on opposite sides. Each of the plates has a single row of three holes for securing the mount to the roof on each of the two plates. Two more fastening holes are located between the extrusions.
These systems require use of jigs to preposition the mounts before photovoltaic cells are mounted. It would be desirable to develop a system that would enable installation system without jigs. It is further desirable to develop a pitched roof mounted system that would reduce the overall installation time by reducing installation steps caused by a two-step process of installing mounts and then installing the photovoltaic cells separate
SMART RACK® is a mounting system for installing solar panels on a pitched asphalt roof by Takashima & Co., Ltd (smart-r@ta.tak.cojp). See SMART RACK General Installation Manual (2009). The system is mounted by a two part mount that comprises a flanged L-clamp and a T-clamp. The solar panel is secured between the flanges on the T-clamp and the L clamp. The T-clamp is inserted into a notched channel in the flanged l-clamp. The clamp does not bear down on the solar panel. Rather a horizontally directed screw fastens the panel to the T-clamp. The L-portion of the flanged L-clamp has two rows of holes to secure the T-clamp to the L-clamp.
There is still a need for a device, system and method for mounting solar panels to a roof that are easy to install, reduce installation time, improve safety by eliminating rails. It would be further advantageous if they can be installed without a jig and can be adjustable in one or more directions. The present invention addresses one or more of these and other needs.